148deab223
This fixes several interlinked problems with the iterators in the presence of multiorder entries. 1. radix_tree_iter_next() would only advance by one slot, which would result in the iterators returning the same entry more than once if there were sibling entries. 2. radix_tree_next_slot() could return an internal pointer instead of a user pointer if a tagged multiorder entry was immediately followed by an entry of lower order. 3. radix_tree_next_slot() expanded to a lot more code than it used to when multiorder support was compiled in. And I wasn't comfortable with entry_to_node() being in a header file. Fixing radix_tree_iter_next() for the presence of sibling entries necessarily involves examining the contents of the radix tree, so we now need to pass 'slot' to radix_tree_iter_next(), and we need to change the calling convention so it is called *before* dropping the lock which protects the tree. Also rename it to radix_tree_iter_resume(), as some people thought it was necessary to call radix_tree_iter_next() each time around the loop. radix_tree_next_slot() becomes closer to how it looked before multiorder support was introduced. It only checks to see if the next entry in the chunk is a sibling entry or a pointer to a node; this should be rare enough that handling this case out of line is not a performance impact (and such impact is amortised by the fact that the entry we just processed was a multiorder entry). Also, radix_tree_next_slot() used to force a new chunk lookup for untagged entries, which is more expensive than the out of line sibling entry skipping. Link: http://lkml.kernel.org/r/1480369871-5271-55-git-send-email-mawilcox@linuxonhyperv.com Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
50 lines
1.9 KiB
C
50 lines
1.9 KiB
C
#include <linux/gfp.h>
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#include <linux/types.h>
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#include <linux/radix-tree.h>
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#include <linux/rcupdate.h>
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struct item {
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unsigned long index;
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unsigned int order;
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};
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struct item *item_create(unsigned long index, unsigned int order);
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int __item_insert(struct radix_tree_root *root, struct item *item);
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int item_insert(struct radix_tree_root *root, unsigned long index);
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int item_insert_order(struct radix_tree_root *root, unsigned long index,
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unsigned order);
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int item_delete(struct radix_tree_root *root, unsigned long index);
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struct item *item_lookup(struct radix_tree_root *root, unsigned long index);
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void item_check_present(struct radix_tree_root *root, unsigned long index);
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void item_check_absent(struct radix_tree_root *root, unsigned long index);
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void item_gang_check_present(struct radix_tree_root *root,
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unsigned long start, unsigned long nr,
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int chunk, int hop);
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void item_full_scan(struct radix_tree_root *root, unsigned long start,
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unsigned long nr, int chunk);
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void item_kill_tree(struct radix_tree_root *root);
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void tag_check(void);
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void multiorder_checks(void);
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void iteration_test(void);
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void benchmark(void);
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struct item *
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item_tag_set(struct radix_tree_root *root, unsigned long index, int tag);
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struct item *
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item_tag_clear(struct radix_tree_root *root, unsigned long index, int tag);
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int item_tag_get(struct radix_tree_root *root, unsigned long index, int tag);
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void tree_verify_min_height(struct radix_tree_root *root, int maxindex);
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void verify_tag_consistency(struct radix_tree_root *root, unsigned int tag);
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extern int nr_allocated;
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/* Normally private parts of lib/radix-tree.c */
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struct radix_tree_node *entry_to_node(void *ptr);
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void radix_tree_dump(struct radix_tree_root *root);
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int root_tag_get(struct radix_tree_root *root, unsigned int tag);
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unsigned long node_maxindex(struct radix_tree_node *);
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unsigned long shift_maxindex(unsigned int shift);
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int radix_tree_cpu_dead(unsigned int cpu);
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